Malicious Office (OOXML) / .DOCX — malware analysis report

Static analysis result for SHA-256 8240717ce45dad96…

MALICIOUS

Office (OOXML) / .DOCX

388.8 KB
MD5: e92a3da0a13e3c5ccf6a67fcb98e2039 SHA-1: b23f8fe81264328c6638697054cdf7c9d9af41e1 SHA-256: 8240717ce45dad96e990f6cfd500228252adde60ae7ba07ac2357aaeb8f11889
462 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The OOXML document contains an embedded RTF object that exploits CVE-2017-11882 through a font record overflow in the Equation Editor. This exploit is designed to download and execute a secondary payload, indicated by the presence of a PE header within the RTF data and the auto-update functionality of the altChunk. The embedded RTF object is the primary mechanism for delivering the malicious payload.

Heuristics 11

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    (in altChunk RTF word/Cambodia.rtf) Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    (in altChunk RTF word/Cambodia.rtf) RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • altChunk imports embedded RTF (RTF injection) critical OOXML_ALTCHUNK_RTF
    Document inlines an embedded RTF via an aFChunk relationship and a <w:altChunk> body element. This is the canonical RTF-injection wrapper used to smuggle RTF exploits (Equation Editor / URL Moniker / objdata) past DOCX-only scanners. Word opens the wrapper and executes the RTF inline. Recursing into the RTF for the exact exploit primitive.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    (in altChunk RTF word/Cambodia.rtf) RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    (in altChunk RTF word/Cambodia.rtf) Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • altChunk RTF auto-updates embedded executable object critical OOXML_ALTCHUNK_RTF_AUTOUPDATE_PE
    OOXML document imports an embedded RTF through altChunk; the RTF contains OLE object data, forces object update, and carries a hex-encoded PE payload. This is a stronger compound exploit-loader shape than a generic altChunk RTF wrapper, but it is not tied to a single CVE unless the nested RTF object primitive also matches one.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    (in altChunk RTF word/Cambodia.rtf) RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    (in altChunk RTF word/Cambodia.rtf) RTF contains ~1344KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    (in altChunk RTF word/Cambodia.rtf) RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    (in altChunk RTF word/Cambodia.rtf) RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://opendope.org/xpaths
    • http://opendope.org/conditions
    • http://opendope.org/questions
    • http://opendope.org/components
    • http://opendope.org/SmartArt/DataHierarchy
    • http://ocsp.verisign.com0
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/main
    • http://schemas.openxmlformats.org/schemaLibrary/2006/main
    • http://schemas.openxmlformats.org/drawingml/2006/chart
    • http://schemas.openxmlformats.org/drawingml/2006/chartDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/diagram
    • http://schemas.openxmlformats.org/drawingml/2006/picture
    • http://schemas.openxmlformats.org/drawingml/2006/spreadsheetDrawing
    • http://schemas.microsoft.com/office/drawing/2008/diagram
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliography
    • http://schemas.openxmlformats.org/drawingml/2006/compatibility
    • http://schemas.openxmlformats.org/drawingml/2006/lockedCanvas
    • https://www.verisign.com/rpa
    • http://csc3-2010-crl.verisign.com/CSC3-2010.crl0D
    • https://www.verisign.com/rpa0
    • http://csc3-2010-aia.verisign.com/CSC3-2010.cer0
    • https://www.verisign.com/cps0*
    • http://logo.verisign.com/vslogo.gif04
    • http://crl.verisign.com/pca3-g5.crl04
    • https://www.globalsign.com/repository/0
    • http://ocsp.globalsign.com/ca/gstsacasha384g40C
    • http://secure.globalsign.com/cacert/gstsacasha384g4.crt0
    • http://crl.globalsign.com/ca/gstsacasha384g4.crl0
    • http://ocsp2.globalsign.com/rootr606
    • http://crl.globalsign.com/root-r6.crl0G

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003a12.bin
fea7ffb447e7fe51f6d499d9aaa4780413780954a83bcb8e0bc5e03e36cafdb5
rtf-objdata-decoded RTF \objdata at offset 0x3A12 685290 bytes
objdata_01_off0015dc18.bin
72bd76599c17052cc34443573f8b849d1967d3263c0e0f0118bc6c097634a998
rtf-objdata-decoded RTF \objdata at offset 0x15DC18 584266 bytes